[SCSI] iscsi class, libiscsi: add iscsi sysfs session state file

This adds a iscsi session state file which exports the session
state for both software and hardware iscsi. It also hooks libiscsi
in.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

4 files changed, 161 insertions, 33 deletions

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index e7942628ac4a..c8c00e173414 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -996,6 +996,7 @@ enum {
         FAILURE_SESSION_IN_RECOVERY,
         FAILURE_SESSION_RECOVERY_TIMEOUT,
         FAILURE_SESSION_LOGGING_OUT,
+        FAILURE_SESSION_NOT_READY,
 };
 
 int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
@@ -1016,6 +1017,12 @@ int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
         session = iscsi_hostdata(host->hostdata);
         spin_lock(&session->lock);
 
+        reason = iscsi_session_chkready(session_to_cls(session));
+        if (reason) {
+                sc->result = reason;
+                goto fault;
+        }
+
         /*
          * ISCSI_STATE_FAILED is a temp. state. The recovery
          * code will decide what is best to do with command queued
@@ -1032,18 +1039,23 @@ int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
                 switch (session->state) {
                 case ISCSI_STATE_IN_RECOVERY:
                         reason = FAILURE_SESSION_IN_RECOVERY;
-                        goto reject;
+                        sc->result = DID_IMM_RETRY << 16;
+                        break;
                 case ISCSI_STATE_LOGGING_OUT:
                         reason = FAILURE_SESSION_LOGGING_OUT;
-                        goto reject;
+                        sc->result = DID_IMM_RETRY << 16;
+                        break;
                 case ISCSI_STATE_RECOVERY_FAILED:
                         reason = FAILURE_SESSION_RECOVERY_TIMEOUT;
+                        sc->result = DID_NO_CONNECT << 16;
                         break;
                 case ISCSI_STATE_TERMINATE:
                         reason = FAILURE_SESSION_TERMINATE;
+                        sc->result = DID_NO_CONNECT << 16;
                         break;
                 default:
                         reason = FAILURE_SESSION_FREED;
+                        sc->result = DID_NO_CONNECT << 16;
                 }
                 goto fault;
         }
@@ -1051,6 +1063,7 @@ int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
         conn = session->leadconn;
         if (!conn) {
                 reason = FAILURE_SESSION_FREED;
+                sc->result = DID_NO_CONNECT << 16;
                 goto fault;
         }
 
@@ -1090,9 +1103,7 @@ reject:
 
 fault:
         spin_unlock(&session->lock);
-        printk(KERN_ERR "iscsi: cmd 0x%x is not queued (%d)\n",
-               sc->cmnd[0], reason);
-        sc->result = (DID_NO_CONNECT << 16);
+        debug_scsi("iscsi: cmd 0x%x is not queued (%d)\n", sc->cmnd[0], reason);
         scsi_set_resid(sc, scsi_bufflen(sc));
         sc->scsi_done(sc);
         spin_lock(host->host_lock);
@@ -1238,7 +1249,8 @@ static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn,
  * Fail commands. session lock held and recv side suspended and xmit
  * thread flushed
  */
-static void fail_all_commands(struct iscsi_conn *conn, unsigned lun)
+static void fail_all_commands(struct iscsi_conn *conn, unsigned lun,
+                              int error)
 {
         struct iscsi_cmd_task *ctask, *tmp;
 
@@ -1250,7 +1262,7 @@ static void fail_all_commands(struct iscsi_conn *conn, unsigned lun)
                 if (lun == ctask->sc->device->lun || lun == -1) {
                         debug_scsi("failing pending sc %p itt 0x%x\n",
                                    ctask->sc, ctask->itt);
-                        fail_command(conn, ctask, DID_BUS_BUSY << 16);
+                        fail_command(conn, ctask, error << 16);
                 }
         }
 
@@ -1258,7 +1270,7 @@ static void fail_all_commands(struct iscsi_conn *conn, unsigned lun)
                 if (lun == ctask->sc->device->lun || lun == -1) {
                         debug_scsi("failing requeued sc %p itt 0x%x\n",
                                    ctask->sc, ctask->itt);
-                        fail_command(conn, ctask, DID_BUS_BUSY << 16);
+                        fail_command(conn, ctask, error << 16);
                 }
         }
 
@@ -1572,7 +1584,7 @@ int iscsi_eh_device_reset(struct scsi_cmnd *sc)
         /* need to grab the recv lock then session lock */
         write_lock_bh(conn->recv_lock);
         spin_lock(&session->lock);
-        fail_all_commands(conn, sc->device->lun);
+        fail_all_commands(conn, sc->device->lun, DID_ERROR);
         conn->tmf_state = TMF_INITIAL;
         spin_unlock(&session->lock);
         write_unlock_bh(conn->recv_lock);
@@ -2018,11 +2030,7 @@ int iscsi_conn_start(struct iscsi_cls_conn *cls_conn)
                 conn->stop_stage = 0;
                 conn->tmf_state = TMF_INITIAL;
                 session->age++;
-                spin_unlock_bh(&session->lock);
-
-                iscsi_unblock_session(session_to_cls(session));
-                wake_up(&conn->ehwait);
-                return 0;
+                break;
         case STOP_CONN_TERM:
                 conn->stop_stage = 0;
                 break;
@@ -2031,6 +2039,8 @@ int iscsi_conn_start(struct iscsi_cls_conn *cls_conn)
         }
         spin_unlock_bh(&session->lock);
 
+        iscsi_unblock_session(session_to_cls(session));
+        wake_up(&conn->ehwait);
         return 0;
 }
 EXPORT_SYMBOL_GPL(iscsi_conn_start);
@@ -2122,7 +2132,8 @@ static void iscsi_start_session_recovery(struct iscsi_session *session,
          * flush queues.
          */
         spin_lock_bh(&session->lock);
-        fail_all_commands(conn, -1);
+        fail_all_commands(conn, -1,
+                        STOP_CONN_RECOVER ? DID_BUS_BUSY : DID_ERROR);
         flush_control_queues(session, conn);
         spin_unlock_bh(&session->lock);
         mutex_unlock(&session->eh_mutex);
diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 0d7b4e79415c..f876b0ae521a 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -30,7 +30,7 @@
 #include <scsi/scsi_transport_iscsi.h>
 #include <scsi/iscsi_if.h>
 
-#define ISCSI_SESSION_ATTRS 18
+#define ISCSI_SESSION_ATTRS 19
 #define ISCSI_CONN_ATTRS 11
 #define ISCSI_HOST_ATTRS 4
 #define ISCSI_TRANSPORT_VERSION "2.0-867"
@@ -221,6 +221,54 @@ static struct iscsi_cls_conn *iscsi_conn_lookup(uint32_t sid, uint32_t cid)
  * The following functions can be used by LLDs that allocate
  * their own scsi_hosts or by software iscsi LLDs
  */
+static struct {
+        int value;
+        char *name;
+} iscsi_session_state_names[] = {
+        { ISCSI_SESSION_LOGGED_IN,      "LOGGED_IN" },
+        { ISCSI_SESSION_FAILED,         "FAILED" },
+        { ISCSI_SESSION_FREE,           "FREE" },
+};
+
+const char *iscsi_session_state_name(int state)
+{
+        int i;
+        char *name = NULL;
+
+        for (i = 0; i < ARRAY_SIZE(iscsi_session_state_names); i++) {
+                if (iscsi_session_state_names[i].value == state) {
+                        name = iscsi_session_state_names[i].name;
+                        break;
+                }
+        }
+        return name;
+}
+
+int iscsi_session_chkready(struct iscsi_cls_session *session)
+{
+        unsigned long flags;
+        int err;
+
+        spin_lock_irqsave(&session->lock, flags);
+        switch (session->state) {
+        case ISCSI_SESSION_LOGGED_IN:
+                err = 0;
+                break;
+        case ISCSI_SESSION_FAILED:
+                err = DID_IMM_RETRY << 16;
+                break;
+        case ISCSI_SESSION_FREE:
+                err = DID_NO_CONNECT << 16;
+                break;
+        default:
+                err = DID_NO_CONNECT << 16;
+                break;
+        }
+        spin_unlock_irqrestore(&session->lock, flags);
+        return err;
+}
+EXPORT_SYMBOL_GPL(iscsi_session_chkready);
+
 static void iscsi_session_release(struct device *dev)
 {
         struct iscsi_cls_session *session = iscsi_dev_to_session(dev);
@@ -259,26 +307,57 @@ static void session_recovery_timedout(struct work_struct *work)
         struct iscsi_cls_session *session =
                 container_of(work, struct iscsi_cls_session,
                              recovery_work.work);
+        unsigned long flags;
 
         dev_printk(KERN_INFO, &session->dev, "iscsi: session recovery timed "
                   "out after %d secs\n", session->recovery_tmo);
 
+        spin_lock_irqsave(&session->lock, flags);
+        switch (session->state) {
+        case ISCSI_SESSION_FAILED:
+                session->state = ISCSI_SESSION_FREE;
+                break;
+        case ISCSI_SESSION_LOGGED_IN:
+        case ISCSI_SESSION_FREE:
+                /* we raced with the unblock's flush */
+                spin_unlock_irqrestore(&session->lock, flags);
+                return;
+        }
+        spin_unlock_irqrestore(&session->lock, flags);
+
         if (session->transport->session_recovery_timedout)
                 session->transport->session_recovery_timedout(session);
 
         scsi_target_unblock(&session->dev);
 }
 
-void iscsi_unblock_session(struct iscsi_cls_session *session)
+void __iscsi_unblock_session(struct iscsi_cls_session *session)
 {
         if (!cancel_delayed_work(&session->recovery_work))
                 flush_workqueue(iscsi_eh_timer_workq);
         scsi_target_unblock(&session->dev);
 }
+
+void iscsi_unblock_session(struct iscsi_cls_session *session)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&session->lock, flags);
+        session->state = ISCSI_SESSION_LOGGED_IN;
+        spin_unlock_irqrestore(&session->lock, flags);
+
+        __iscsi_unblock_session(session);
+}
 EXPORT_SYMBOL_GPL(iscsi_unblock_session);
 
 void iscsi_block_session(struct iscsi_cls_session *session)
 {
+        unsigned long flags;
+
+        spin_lock_irqsave(&session->lock, flags);
+        session->state = ISCSI_SESSION_FAILED;
+        spin_unlock_irqrestore(&session->lock, flags);
+
         scsi_target_block(&session->dev);
         queue_delayed_work(iscsi_eh_timer_workq, &session->recovery_work,
                            session->recovery_tmo * HZ);
@@ -327,10 +406,12 @@ iscsi_alloc_session(struct Scsi_Host *shost,
 
         session->transport = transport;
         session->recovery_tmo = 120;
+        session->state = ISCSI_SESSION_FREE;
         INIT_DELAYED_WORK(&session->recovery_work, session_recovery_timedout);
         INIT_LIST_HEAD(&session->host_list);
         INIT_LIST_HEAD(&session->sess_list);
         INIT_WORK(&session->unbind_work, __iscsi_unbind_session);
+        spin_lock_init(&session->lock);
 
         /* this is released in the dev's release function */
         scsi_host_get(shost);
@@ -444,7 +525,10 @@ void iscsi_remove_session(struct iscsi_cls_session *session)
          * If we are blocked let commands flow again. The lld or iscsi
          * layer should set up the queuecommand to fail commands.
          */
-        iscsi_unblock_session(session);
+        spin_lock_irqsave(&session->lock, flags);
+        session->state = ISCSI_SESSION_FREE;
+        spin_unlock_irqrestore(&session->lock, flags);
+        __iscsi_unblock_session(session);
         iscsi_unbind_session(session);
         /*
          * If the session dropped while removing devices then we need to make
@@ -661,16 +745,23 @@ EXPORT_SYMBOL_GPL(iscsi_recv_pdu);
 
 void iscsi_conn_error(struct iscsi_cls_conn *conn, enum iscsi_err error)
 {
+        struct iscsi_cls_session *session = iscsi_conn_to_session(conn);
         struct nlmsghdr *nlh;
         struct sk_buff  *skb;
         struct iscsi_uevent *ev;
         struct iscsi_internal *priv;
         int len = NLMSG_SPACE(sizeof(*ev));
+        unsigned long flags;
 
         priv = iscsi_if_transport_lookup(conn->transport);
         if (!priv)
                 return;
 
+        spin_lock_irqsave(&session->lock, flags);
+        if (session->state == ISCSI_SESSION_LOGGED_IN)
+                session->state = ISCSI_SESSION_FAILED;
+        spin_unlock_irqrestore(&session->lock, flags);
+
         skb = alloc_skb(len, GFP_ATOMIC);
         if (!skb) {
                 dev_printk(KERN_ERR, &conn->dev, "iscsi: gracefully ignored "
@@ -1246,6 +1337,15 @@ iscsi_session_attr(fast_abort, ISCSI_PARAM_FAST_ABORT, 0);
 iscsi_session_attr(abort_tmo, ISCSI_PARAM_ABORT_TMO, 0);
 iscsi_session_attr(lu_reset_tmo, ISCSI_PARAM_LU_RESET_TMO, 0);
 
+static ssize_t
+show_priv_session_state(struct class_device *cdev, char *buf)
+{
+        struct iscsi_cls_session *session = iscsi_cdev_to_session(cdev);
+        return sprintf(buf, "%s\n", iscsi_session_state_name(session->state));
+}
+static ISCSI_CLASS_ATTR(priv_sess, state, S_IRUGO, show_priv_session_state,
+                        NULL);
+
 #define iscsi_priv_session_attr_show(field, format)                     \
 static ssize_t                                                          \
 show_priv_session_##field(struct class_device *cdev, char *buf)         \
@@ -1472,6 +1572,7 @@ iscsi_register_transport(struct iscsi_transport *tt)
         SETUP_SESSION_RD_ATTR(abort_tmo, ISCSI_ABORT_TMO);
         SETUP_SESSION_RD_ATTR(lu_reset_tmo,ISCSI_LU_RESET_TMO);
         SETUP_PRIV_SESSION_RD_ATTR(recovery_tmo);
+        SETUP_PRIV_SESSION_RD_ATTR(state);
 
         BUG_ON(count > ISCSI_SESSION_ATTRS);
         priv->session_attrs[count] = NULL;
diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index 71eda24114e9..278011fb3c2f 100644
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -135,6 +135,14 @@ static inline void* iscsi_next_hdr(struct iscsi_cmd_task *ctask)
         return (void*)ctask->hdr + ctask->hdr_len;
 }
 
+/* Connection's states */
+enum {
+        ISCSI_CONN_INITIAL_STAGE,
+        ISCSI_CONN_STARTED,
+        ISCSI_CONN_STOPPED,
+        ISCSI_CONN_CLEANUP_WAIT,
+};
+
 struct iscsi_conn {
         struct iscsi_cls_conn   *cls_conn;      /* ptr to class connection */
         void                    *dd_data;       /* iscsi_transport data */
@@ -227,6 +235,17 @@ struct iscsi_pool {
         int                     max;            /* Max number of elements */
 };
 
+/* Session's states */
+enum {
+        ISCSI_STATE_FREE = 1,
+        ISCSI_STATE_LOGGED_IN,
+        ISCSI_STATE_FAILED,
+        ISCSI_STATE_TERMINATE,
+        ISCSI_STATE_IN_RECOVERY,
+        ISCSI_STATE_RECOVERY_FAILED,
+        ISCSI_STATE_LOGGING_OUT,
+};
+
 struct iscsi_session {
         /*
          * Syncs up the scsi eh thread with the iscsi eh thread when sending
diff --git a/include/scsi/scsi_transport_iscsi.h b/include/scsi/scsi_transport_iscsi.h
index 404f11d331d6..0e869d9a3856 100644
--- a/include/scsi/scsi_transport_iscsi.h
+++ b/include/scsi/scsi_transport_iscsi.h
@@ -149,13 +149,6 @@ extern void iscsi_conn_error(struct iscsi_cls_conn *conn, enum iscsi_err error);
 extern int iscsi_recv_pdu(struct iscsi_cls_conn *conn, struct iscsi_hdr *hdr,
                           char *data, uint32_t data_size);
 
-
-/* Connection's states */
-#define ISCSI_CONN_INITIAL_STAGE        0
-#define ISCSI_CONN_STARTED              1
-#define ISCSI_CONN_STOPPED              2
-#define ISCSI_CONN_CLEANUP_WAIT         3
-
 struct iscsi_cls_conn {
         struct list_head conn_list;     /* item in connlist */
         void *dd_data;                  /* LLD private data */
@@ -169,19 +162,21 @@ struct iscsi_cls_conn {
 #define iscsi_dev_to_conn(_dev) \
         container_of(_dev, struct iscsi_cls_conn, dev)
 
-/* Session's states */
-#define ISCSI_STATE_FREE                1
-#define ISCSI_STATE_LOGGED_IN           2
-#define ISCSI_STATE_FAILED              3
-#define ISCSI_STATE_TERMINATE           4
-#define ISCSI_STATE_IN_RECOVERY         5
-#define ISCSI_STATE_RECOVERY_FAILED     6
-#define ISCSI_STATE_LOGGING_OUT         7
+#define iscsi_conn_to_session(_conn) \
+        iscsi_dev_to_session(_conn->dev.parent)
+
+/* iscsi class session state */
+enum {
+        ISCSI_SESSION_LOGGED_IN,
+        ISCSI_SESSION_FAILED,
+        ISCSI_SESSION_FREE,
+};
 
 struct iscsi_cls_session {
         struct list_head sess_list;             /* item in session_list */
         struct list_head host_list;
         struct iscsi_transport *transport;
+        spinlock_t lock;
 
         /* recovery fields */
         int recovery_tmo;
@@ -190,6 +185,7 @@ struct iscsi_cls_session {
 
         int target_id;
 
+        int state;
         int sid;                                /* session id */
         void *dd_data;                          /* LLD private data */
         struct device dev;      /* sysfs transport/container device */
@@ -214,6 +210,7 @@ struct iscsi_host {
 /*
  * session and connection functions that can be used by HW iSCSI LLDs
  */
+extern int iscsi_session_chkready(struct iscsi_cls_session *session);
 extern struct iscsi_cls_session *iscsi_alloc_session(struct Scsi_Host *shost,
                                         struct iscsi_transport *transport);
 extern int iscsi_add_session(struct iscsi_cls_session *session,